Fibrous absorbent articles having enhanced deodorizing properties

ABSTRACT

Fibrous absorbent articles such as disposable diapers, catamenial devices, wound dressings, bandages, incontinence pads, wipes, underwear, shoe inserts and the like, contain an effective amount of crystalline, siliceous molecular sieve having pore diameters of at least about 5.5 Angstroms and a relatively low capacity for adsorbed water, and exhibit enhanced deodorizing properties with respect to the body fluids intended to be absorbed.

This is a continuation-in part of U.S. patent application Ser. No.67,977, filed June 30, 1987, now U.S. Pat. No. 4,795,482 hereinincorporated by reference.

This invention relates to fibrous absorbent articles intended for theabsorption of body fluids, such as disposable diapers, catamenialdevices (e.g., tampons and sanitary napkins), wound dressings, bandages,incontinence pads, wipes, disposable underwear, shoe inserts and thelike, that have deodorizing properties. In particular, the fibrousabsorbent articles comprise crystalline siliceous molecular sievecomponent to provide enhanced removal of odors.

Fibrous absorbent articles have been known for some time and incorporatea plurality of fibers arranged in a structure to absorb and retain bodyfluids. The body fluids retained in these absorbent articles can emitunpleasant odors.

Odors from body fluids may be produced by a wide variety of chemicalcompounds that either are produced in the body and passed from the bodysuch as excrement, catamenial fluids and sweat or seepage from wounds,and/or the odors may originate from microbial action on such bodyfluids. The odors may be produced by ammonia and ammonium compounds,amines, lower carboxylic acids or esters such as isovaleric acid,aldehydes, sulfur compounds, and the like. The threshold concentrationof many of these odor-producing compounds for olfactory sensing byhumans is relatively low, e.g., often less than parts per million byvolume in air. For instance, ammonia can generally be detected at lessthan 40 parts by volume per billion; hydrogen sulfide, about 1 part perbillion and isovaleric acid, less than about 100 parts per billion.

Heretofore, various proposals have been made to mitigate these odorssuch as the use of perfumes to mask the odors that may emanate from theabsorbent article. Other proposals include the use of substances toremove the odor-causing compounds.

The odor-causing compounds may be removed by several mechanisms. Forexample, the odoriferous substance can be chemically reacted to form anon odoriferous and/or non volatile compound by chemical reaction orsorbed into a non-volatile substance, e.g., a solid or liquid. For asorbent to be effective for deodorizing, especially for odors from bodyfluids that are characterized as having very low olfactory thresholds,it is essential that the sorbent be capable of removing, in itsenvironment, virtually all the odoriferous compounds regardless of theconcentration of the compound. Thus, the sorbent must be able to sorb anodoriferous compound when it is present in even trace amounts and thesorbent must be able to retain the sorbed odoriferous compound even whenit approaches saturation.

The use of solid adsorbents to deodorize fibrous absorbent articlesintended for absorption of body fluids has been proposed. By far themost commonly suggested solid adsorbent for odor suppression isactivated charcoal or active carbon, although silica gel, activatedalumina, kieselguhr, fullers earth and other clay minerals and zeolites,alone or in combination, have also been proposed as odor "adsorbents".

Japanese patent application publication No. 70200, dated June 10, 1977,discloses fibrous articles such as paper and loose fibers. The fibrousarticle is first heat treated, e.g., at 100° to 450° C. from 1 to 100minutes and then treated with a zeolite (which has been treated withwater repellant), synthetic zeolite, active charcoal or calcium-typebentonite.

Japanese patent application publication No. 138452, dated Aug. 17, 1983,discloses a sanitary towel containing an absorbent fabric having on itsouter surface a zeolite and ascorbic acid compound such as the sodium orpotassium salts of ascorbic acid or arabo ascorbic acid, or acylderivatives of ascorbic acid or arabo ascorbic acid. The zeolite ispreferably zeolite X or Y having large pores.

Another type of sanitary towel is disclosed in Japanese published patentapplication No. 31425 dated Mar. 30, 1981, in which a deodorizing agentis coated with a water-absorbing polymer. The deodorizing agent ismagnesium silicate, aluminum silicate, calcium silicate, silica gel,chlorella powder, chlorophyll powder, ion exchanging resin powder,active carbon or zeolite.

A diaper containing molecular sieves is disclosed in European PatentApplication No. 41569, dated Dec. 16, 1981. The diaper is constructed toprovide a fabric layer on the side worn next to the skin of the user anda fabric layer incorporating a zeolite on the opposite side. The zeoliteis stated to be a material capable of preferentially incorporatingammonium ions such as zeolite F, W or A, synthetic gismondine typezeolite, synthetic or natural mordenite, chabazite, phillipsite orclinoptilolite.

Japanese published patent application No. 268253, dated Nov. 27, 1986,discloses hygenic products in which a holmite series mineral isdispersed or impregnated into a natural or synthetic fiber from whichthe hygenic product is manufactured. The patent discloses that the wateradsorption ratio of holmite (e.g., sepiolite) is about four times thatof natural zeolite and that the product made using the holmite canadsorb and deodorize sweat, excretion and odor produced by the body. Thehygenic product can be used for diapers, sanitary napkins, tampons,towels and underwear.

Japanese patent application publication No. 95042, dated May 31, 1984,discloses a biaxially stretched sheet of polymer containing 20 to 70weight percent of a deodorizing powder such as activated carbon,zeolite, diatomaceous earth, as clay. The stretched sheet has fineholes, e.g., 0.1 to 5 microns. The sheet may be packed with absorbent toprovide sanitary towels or sanitary napkins having good liquidabsorption, liquid leak resistance, deodorizing properties and airpermeability.

Japanese published patent application No. 141857, dated Nov. 5, 1979,discloses the lamination of two sheets of material to fix between thesheets a deodorizing powder such as active carbon, zeolite, ion exchangeresin, carboxy methylcellulose, or polyethylene glycol.

Zeolites and molecular sieves have been incorporated into fibrousproducts for reasons other than deodorizing. For example, Japanesepublished patent application No. 138658, dated June 26, 1986, disclosesthe use of water impermeable, urethane films for sanitary briefs ordiaper covers wherein the film contains antibacterial metal ions whichare ion-exchanged into zeolites. The zeolites have specific surfaceareas greater than 150 square meters per gram and a silica to aluminaratio below 14. The antibacterial ions may be silver, copper or zinc.Similarly, U.S. Pat. No. 4,525,410, issued June 25, 1985, disclosesfiber articles in which at least a portion of the fibers are stucktogether at their intersections and zeolite particles are incorporatedand retained in the structure. The zeolite is required to have aspecific surface area of at least 150 square meters per gram and asilica to alumina ratio less than 14, preferably, less than 11. Thezeolite is ion-exchanged with silver, copper or zinc.

Molecular sieves have been proposed for other odor control applications.For instance, in U.S. Pat. 4,437,429, the use of a hydrated zeolite inadmixture with clay is proposed as being particularly useful for thecontrol of odors from pet litter, it being observed that the use ofzeolites by themselves as litter material has generally beenunsuccessful due to their poor water adsorption properties as comparedwith clays. For the adsorption of certain odors from animal litter usinga mixture of clays and zeolites, it is proposed in U.S. Pat. No.4,437,429 that the zeolite constituent not only be employed in itshydrated state, but also that the water of hydration be the originalwater of hydration. It is said to be not sufficient that water is addedto a previously heat-treated zeolite from which the original water ofhydration was driven off.

In general, when zeolites have been utilized for odor suppression, thepreferred species have been those with a low framework Si/Al ratio and ahigh degree of adsorption capacity for water or other highly polarmolecules such as ammonia or hydrogen sulfide. The disclosure of theaforesaid U.S. Pat. No. 4,437,429 is somewhat remarkable for itsspecific disclosure of many of the class of so-called high silicazeolites which are synthesized using organic templating agents such asthe tetraalkylammonium ions. These include ZSM-5, ZSM-11, ZSM-12 andZSM-23. The preferred zeolite species is the natural mineralclinoptilolite, however, which has a nominal framework SiO₂ /Al₂ O₃molar ratio of about ten. U.S. Pat. No. 4,648,977 discloses usinghigh-silica molecular sieves, including the silica polymorph silicalite,to adsorb toxic organic materials, including mercaptans, from aqueousmedia for water purification purposes.

SUMMARY OF THE INVENTION

In accordance with this invention, fibrous absorbent articles forabsorbing body fluids are provided which contain an effective amount ofmolecular sieve to reduce the emanation of odors from the fibrousabsorbent article, said molecular sieve comprising a crystallinesiliceous molecular sieve in which at least about 90 percent of theframework tetrahedral oxide units are SiO₂ tetrahedra, which has porediameters of at least 5.5 Angstroms and has a capacity for adsorbedwater not greater than 10 weight percent under standard conditions asdescribed herein.

The fibrous absorbent articles of this invention essentially eliminatecharacteristic odors from various body fluids. Hence the fibrousabsorbent articles are particularly attractive for use in disposablediapers, catamenial devices, wound dressings, bandages, incontinencepads, sanitary towels, disposable underwear, shoe inserts, wipes and thelike.

CRYSTALLINE SILICEOUS MOLECULAR SIEVES

The fibrous absorbent articles of this invention contain crystallinesiliceous molecular sieve. The crystalline siliceous molecular sieve hasat least about 90, and preferably at least about 95, percent of theframework tetrahedral oxide units being SiO₂ tetrahedra and have asorptive capacity for water of less than 10 weight percent understandard conditions. The water adsorption capacity of molecular sievesis generally measured based on a defined temperature, vapor pressure andtime. For the purposes herein, a "Standard Condition" will be referredto when describing water adsorption capacity which conditions shall be25° C., a water vapor pressure of 4.6 torr and a time of two hours.

In the case of aluminosilicate molecular sieves, those most often usedin the practice of the invention have a framework SiO₂ /Al₂ O₃ molarratio of from at least about 18, say, about 35 to infinity, andpreferably from 200 to 500. All of the siliceous molecular sievessuitably employed have pore diameters of at least 5.5 Angstroms,preferably at least 6.2 Angstroms. Preferably the adsorption capacityfor water vapor is less than 6 weight percent at Standard Conditions.

The efficacy of the molecular sieves employed in the practice of thepresent invention is not dependent upon the presence of the water ofhydration present in the internal cavities of the microporous structureas a result of their hydrothermal formation. In fact, at least a majorproportion, usually substantially all, of this original water ofhydration is often removed in the process of removing any pore-blockingtemplating agent which may be present in the as-synthesized form of themolecular sieve. Calcination effectively removes the organic moieties.Also, water washing or washing with a caustic or dilute mineral acidsolution is advantageously utilized to remove extraneous inorganicsynthesis reagents from the pore system. Lowering of the alkali metalcontent, particularly the non zeolitic, i.e., occluded alkali metalcompounds, can also be beneficial. These procedures also serve to removethe original water of hydration.

The siliceous molecular sieves suitably employed in the practice of theinvention include the microporous crystalline aluminosilicates, i.e. thezeolitic molecular sieves as well as the so-called silica polymorphs.With respect to the latter compositions, their crystal lattices areideally formed entirely of SiO₂ tetrahedral units, but theas-synthesized forms commonly contain at least trace amounts of aluminumderived from aluminum impurities in the synthesis reagents. Thealuminosilicate molecular sieves comprise the large class of well-knowncrystalline zeolites. These high-silica molecular sieves are eithercommercially available or are prepared by methods, well-known in theart, involving direct hydrothermal synthesis or involving certain typesof crystal lattice dealuminations. A comprehensive review article by E.M. Flanigen concerning both "high" Si/Al zeolites and silica molecularsieves is published in "Proc. 5th Int. Conf. Zeolites, Naples, 1980", L.V. C. Rees, ed., Heyden, London, pp. 760-780. This article isincorporated herein by reference.

It is a critical aspect of the present invention that the adsorptivecapacity for water of the siliceous molecular sieve is less than 10weight percent under Standard Conditions. It is another critical aspectthat the number of AlO₂ ⁻ tetrahedral units of the crystal lattice, ifpresent at all, be very small compared with the number of SiO₂tetrahedral units. It has been observed that there appears to be somecorrelation between the framework SiO₂ /Al₂ O₃ ratio and the adsorptivecapacity for water, i.e., the so-called hydrophobicity, of siliceousmolecular sieves. It has also been observed, however, that in certaininstances, for example in the case of zeolite Beta, a molecular sievehaving a highly siliceous crystal framework may not be sufficientlyhydrophobic or possess the desired sorptivity. Thus, while manymolecular sieves with framework SiO₂ /Al₂ O₃ molar ratios of greaterthan about 18, and especially greater than about 35, exhibit therequisite degree of hydrophobicity for use in the present invention,some do not. It may also be advantageous, in some instances, to have thealkali metal content of the molecular sieve low, i.e., not greater than0.2 wt. %, anhydrous basis.

Whatever the reason, it is found that the class of medium to large poresiliceous molecular sieves defined hereinabove, preferably in the formin which the original, as-synthesized water of hydration has beensubstantially removed, function in an extraordinary manner with respectto odor elimination from body fluids. Many of the synthetic zeolitesprepared using organic templating agents are readily prepared in ahighly siliceous form--some even from reaction mixtures which have nointentionally added aluminum. These zeolites are markedly organophilicand include ZSM-5 (U.S. Pat. No. 3,702,886); ZSM-11 (U.S. Pat. No.3,709,979); ZSM-35 (U.S. Pat. No. 4,016,245); ZSM-23 (U.S. Pat. No.4,076,842); and ZSM-38 (U.S. Pat. No. 4,046,859) to name only a few. Ithas been found that the silica molecular sieves known as silicalite andF-silicalite are particularly suitable for use in the present inventionand are thus preferred. These materials are disclosed in U.S. Pat. Nos.4,061,724 and 4,073,865, respectively. To the extent the aforesaidsiliceous sieves are synthesized to have SiO₂ Al₂ O₃ ratios greater than35, they are frequently suitable for use in the present process withoutany additional treatment to increase their degree of hydrophobicity.Molecular sieves which cannot be directly synthesized to have bothsufficiently high Si/Al and/or degree of hydrophobicity ratios can besubjected to dealumination techniques, fluorine treatments and the like,which result in organophilic zeolite products. High temperature steamingprocedures for treating zeolite Y which result in hydrophobic productforms are reported by P. K. Maher et al., "Molecular Sieve Zeolites,"Advan. Chem. Ser. 101, American Chemical Society, Washington, D.C.,1971, p. 266. A more recently reported procedure applicable to zeolitespecies generally involves dealumination and the substitution of siliconinto the dealuminated lattice site. This process is disclosed in U.S.Pat. No. 4,503,023 issued Mar. 5, 1985 to Skeels, et al. Halogen orhalide compound treatments for zeolites to increase their hydrophobicityare disclosed in U.S. Pat. Nos. 4,569,833 and 4,297,335.

With respect to the foregoing adsorbents, it is important that the poresystem be open so that the internal cavities of the crystals beaccessible to the odor molecules. In the case of the aluminosilicates orsilica polymorphs produced using large organic templating ions such astetraalkylammonium ions, it is necessary to remove charge balancingorganic ions and any occluded templating material in order to permitadsorption of the odor molecules. In such a removal process and also inthe removal of inorganic debris, the original water of hydration is alsoremoved. Upon exposure to the atmosphere a portion of the water ofhydration is reacquired, but this does not affect the generalperformance of the molecular sieve, i.e., the molecular sieve can beemployed in either a hydrated or dehydrated state, but in general thedehydrated state is preferred. In the case of most of the dealuminationprocedures referred to above, the original water of dehydration is alsoremoved, and can similarly be replaced, if desired.

It should be pointed out that it is the framework SiO₂ /Al₂ O₃ ratiowhich is important. This is not necessarily the same ratio as would beindicated by conventional wet chemical analysis. Especially is this thecase when dealumination has been accomplished by high temperaturesteaming treatments wherein aluminum-containing tetrahedral units of thezeolite are destroyed, but the aluminum values remain, at least in part,in the zeolite crystals. For such zeolite products resort must be had toother analytical methods such as X-ray and NMR. One such steam-treatedzeolite Y composition, denominated LZ-10, has been found to beparticularly useful in the practice of the present process, especiallywhen utilized in combination with the silica polymorph silicalite. Theprocess for preparing LZ-10 is described in detail in U.S. Pat. No.4,331,694 and in U.S. patent application Ser. No. 880,561 filed Feb. 23,1978, herein incorporated by reference. A benefit appears to be obtainedby such a combination of molecular sieves in all proportions, but eachtype of adsorbent is preferably present in an amount of at least 10percent based on the total weight of the two adsorbents (hydrated weightbasis).

The crystalline siliceous molecular sieve may be in any suitable form.Typically, the molecular sieve is in its powder form or may beaggregated into larger particles, e.g., about 0.5 to 500 or more micronsin major dimension. The aggregates may be any convenient shape, e.g.,spheres, cylinders, free form, or the like. Binders such as silica oralumina binders may be used in forming aggregates. The aggregates maycontain other desirable components for the fibrous absorbent article asherein later discussed.

FIBROUS ABSORBENT ARTICLES

The fibrous absorbent article comprises fibrous material capable ofabsorbing body fluids such as catamenial fluids, urine, sweat, seepagefrom wounds and the like. Various fibrous materials that have beenproposed as absorbents include wood fluff, cellulosic derivatives(rayon), cotton, synthetic polymer and synthetic polymer blends (e.g.,polyester, polypropylene, nylon, polyethylene, and the like).

The fibrous material may be arranged to form a woven or non-wovenstructure which may be in the form of a batt or a web or a tissue orfabric or an open pore foam. These structures can be formed by anyconvenient technique and include dry and wet techniques.

The fibrous absorbent article may essentially be a unicomponent articleor may be a multicomponent article. The specific arrangement will oftenbe chosen depending upon the application and the other components of thefibrous absorbent. Exemplary of unicomponent articles are those in whichthe fibrous material essentially constitutes the article such as papertowels, non-woven fabric in the form of underwear, shoe inserts and thelike in which the siliceous molecular sieve is incorporated into thefibrous structure. Multicomponent articles may employ layers or areas ofdifferent or the same materials. For example, a sanitary napkin mayconsist of a plurality of fibrous absorption fabrics or a wipe may havea plurality of fibrous absorption tissues. Dissimilar components in thefibrous absorption article may perform different functions. Thus, afibrous batt may be positioned between an essentially water impermeableexterior sheet and a permeable, but non-absorptive body contact sheet inthe construction of a diaper, bandage or sanitary napkin. Also, astructural web of a stronger, but, perhaps, substantiallynon-absorptive, material may be used to provide a frame for attachingthe fibrous material and the structural web can provide significantstrength to the resulting fibrous absorbent article.

Other components which may be contained in a fibrous absorbent articleinclude superabsorbent materials in the case of catamenial devicesincontinence pads, towels and diapers. Superabsorbents are capable ofabsorbing large amounts of water, e.g., often up to ten times or moreits dry weight. Superabsorbents are typically water swellable polymerssuch as polysaccharides, modified and regenerated polysaccharides,grafted polysaccharides, polyacrylates, polyacrylonitriles (especiallypolyacrylonitriles grafted onto polyvinyl alcohol), polyvinyl alcohol,hydrophyllic polyurethanes, partially hydrolyzed polyacrylamides,sulfonated polystyrene, sulfonated polyethers, poly(alkylene oxide), andthe like. The superabsorbents may be provided in any convenient formsuch as fibers, spheres, bits of film, or coatings on other componentsin the fibrous absorbent.

Other components that may be present include medicants, other absorbentsand adsorbents (including sodium bicarbonate, activated carbon, clays,silica gel, and other molecular sieves having high water sorptivityand/or ammonium ion sorptivity such as zeolites X, Y, W, A,clinoptilolite; mordenite, etc.), and the like. Fragrances may beemployed, but consideration must be given to the sorptivity of thesiliceous molecular sieve. In general, larger molecular size fragrancesare preferred.

The amount of the crystalline siliceous molecular sieve employed in thefibrous absorbent articles should be sufficient to significantly reduce,if not essentially eliminate, the odors from the body fluid intended tobe absorbed during use. Thus, depending upon the use of the fibrousabsorbent, the amount of crystalline siliceous molecular sieve desiredfor incorporation may vary. In applications such as diapers wheresubstantial odoriferous fluid may need to be retained, larger amountsmay be desired than in applications such as bandages. The siliceousmolecular sieves employed in the fibrous absorbent article of thisinvention are characterized as being very effective when used inrelatively small amounts. In part this is due to the adsorption activityof these molecular sieves and in part, due to the selectivity of thesiliceous molecular sieves toward the odor-causing compounds emanatingfrom body fluids. For example, as little as 0.1 gram of siliceousmolecular sieve has been found to effectively remove odors fromcatamenial devices.

The amounts of siliceous molecular sieve used in a fibrous absorptionarticle may be characterized by various means, i.e., on a per articlebasis, on a volume basis, on an effective area basis, etc. Because ofthe wide variety of materials, construction and shape of fibrousabsorbent articles and of the fibrous structures, difficulty exists inestablishing a sound comparative basis for describing silieous molecularsieve content. In general, however, the siliceous molecular sievecontent may be described in terms of grams per unit volume of thefibrous structure in its uncompressed, dry state or grams per uniteffective area (i.e., the area of the major plane of the fibrousstructure). Generally the amount of crystalline siliceous molecularsieve is at least about 0.001 and sometimes up to about 50, preferably,0.01 to 25 grams per 100 cubic centimeters of fibrous material volume.Often, the amount of crystalline siliceous molecular sieve is betweenabout 0.05 to 10 grams per 100 cubic centimeters of volume. Typically,the siliceous molecular sieve is provided in an amount of about 0.01 to25 grams, e.g., about 0.05 to 10, grams per 100 square centimeters ofeffective area. For various applications, e.g., catamenial devices, thecrystalline siliceous molecular sieve is usually used in an amount ofabout 0.01 to 10 grams per pad or tampon; for diapers, about 0.05 to 50grams per diaper; for shoe pads, about 0.05 to 10 grams per pad.

The crystalline siliceous molecular sieve may be incorporated into thefibrous absorbent in any suitable manner. For instance, it can beloosely dispersed within a batt or tissue containing fibrous material.Generally, however, it is preferred that the molecular sieve besufficiently immobilized in the fibrous absorbent that it does notreadily migrate to the body. The molecular sieve may be, for example,retained within the fibrous absorbent in a fluid permeable containerthrough which the molecular sieve cannot pass. Thus, molecular sieve maybe positioned between two sheets of permeable thermoplastic which havebeen heat sealed. The sheets may be perforated with small holes toachieve the desired permeability. A particularly attractive means forsecuring the siliceous molecular sieve in a fibrous absorbent article isto place the molecular sieve between two layers of tissue or fabric thatis absorbent and then adhere the layers together, e.g., mechanically byneedle punching or securing; by gluing, e.g., with latex; or by heatsealing. The molecular sieve-containing composite can be readily handledincluding cut and shaped and incorporated into the fibrous absorbentarticle.

Another means for providing the molecular sieve includes using themolecular sieve as a filler, e.g., in an amount of at least about 1,say, about 1 to 70, e.g., about 5 to 70, percent by weight, in apolymeric film or paper-type material which is intended to contain thefibrous material or be incorporated within the fibrous absorbentarticle. Alternatively, or in addition, the molecular sieve maysimilarly be incorporated into the fibrous material which is preparedfrom a polymeric melt and/or any superabsorbent employed. Molecularsieve may also be incorporated by the use of an adhesive material on atleast a portion of the fibrous absorbent article (e.g., linings, fibrousmaterial, structural elements, etc.) or even by contacting the molecularsieve with thermoplastic material (e.g., linings, fibrous material,structural elements, etc.) while the thermoplastic material is at asufficiently high temperature to be tacky.

Drawings

FIG. 1 depicts perspective view of a sanitary napkin; and

FIG. 2 is a cross-sectional view of the sanitary napkin of FIG. 1through lines 2--2.

FIG. 1 illustrates a sanitary napkin 10 having a fabric overlay 12. FIG.2 is a cross-sectional view showing the construction in the napkin 10.With reference to FIG. 2, the fabric overlay 12 is a moisture-permeablenon-woven fabric and has immediately to its interior, amoisture-impermeable layer 14 which surrounds the sides and the bottomof the sanitary napkin. Within the volume defined by the fabric overlay12 and the moisture-impermeable layer 14 is contained fibrous batts 16which serve to absorb liquid. Particles of superabsorbent 18 are alsodepicted within batts 16. As shown, non-woven fabrics 20 and 22 form asandwich structure and are shown intermediate batts 16 and are fluidpermeable. In between fabrics 20 and 22 is dispersed siliceous molecularsieve. Fabrics 20 and 22 are secured together by latex. Alternatively,fabrics 20 and 22 may be positioned immediately adjacent the bottom orthe top of the interior of the napkin 10.

EXAMPLES

The invention is illustrated by the examples appearing hereinafter. Bodyodors, e.g., for catamenial fluids, can contain lower carboxylic acidsand amines. Examples 1 to 19 serve to illustrate the effectiveness ofsiliceous molecular sieves in removing isovaleric acid andtriethylamine, odoriferous components which are typically present incatamenial fluids. For examples 1 to 20, a number of high silicaaluminosilicates and silica polymorphs were exposed to various odoroussubstances in a reproducible and consistent manner to determine theabsolute or relative amounts of odors adsorbed. In the experiments 40ml. screwcap vials equipped with Teflon-lined silicone rubber septa wereused. The vials were measured to have a capacity of 43.5±0.1 ml.

The activated charcoal adsorbent used was 70/80 mesh chromatographicgrade from Analabs, Inc., Hamden, Conn., and was labeled ANASORB grade.The adsorbent of interest was weighed into the vial and the vial wascapped. The adsorbate was added to the sealed vial with a Hamiltonsyringe. Samples were shaken by hand to mix the liquid/solid/vaporphases and the vapors in the headspace of the vials were analyzed by gaschromatography within 5 to 20 minutes after weighing and mixing.

To determine the maximum vapor concentrations of the volatile testcompounds in air, the pure compounds were placed into 43.5 ml. capacityvials and stored for at least one hour prior to analysis. Generally 2microliter aliquots from the headspace of the 43.5 ml. vials wereanalyzed; 2 microliters of room air was injected to maintain consistentatmospheric pressure.

Prior to and after each sample injection the syringe needle was placedinto a 200° C. syringe cleaner under vacuum (estimated pressure lessthan 5×10⁻³ torr). As a heat source a 100 watt light bulb was placedover the syringe at a distance of 1 to 2 inches. This was done toeliminate any cross contamination from vapor molecules adsorbed on theTeflon parts of the syringe. The heating under vacuum was done forapproximately 5 minutes prior to use. Analysis of room air after thiscleaning procedure showed no contamination in the syringe.

Gas chromatographic analytical techniques were employed to measure theconcentration of odor components in the headspace of the sample vials.The column was a 0.32 mm. I.D.×30 meters, fused silica adsorbentcapillary containing a 1 micron internal coating of polyethylene glycolas the adsorbent. A flame ionization detector was utilized to determineretention times. The oven conditions were 50° C. for four minutes andthen raised to 150° C. at the rate of 10° C. per minute.

EXAMPLE 1

(a) Ten microliters of isovaleric acid were placed in an empty capped43.5 ml. vial and the headspace vapors determined in accordance with theabove described test procedures were found to exist in a concentrationof 668 ppm. The retention time was 4.83 minutes with a small additionalpeak present at 4.22 minutes.

(b) To the vial containing the isovaleric acid used in part (a) abovewas added 0.5 grams of sodium bicarbonate. The concentration ofisovaleric acid in the vial headspace was found to be reduced to aconcentration of 2.2 ppm. The 4.22 peak observed in part (a) was stillpresent, and in addition new peaks at 4.87, 6.36, 6.61 and 6.94 wereproduced.

(c) To the vial containing the isovaleric acid used in part (a) abovewas added 0.5 grams of an equal parts by weight mixture of activatedsilicalite and zeolite LZ-10. The concentration of isovaleric acid inthe vial headspace was found to be reduced to less than the waschromatograph detector limit which was about 0.82 ppm. and in additionthe peak at 4.22 was removed without the introduction of any new peaks.

EXAMPLES 2-9

Eight different adsorbent materials were tested for their ability todeodorize the airspace over triethylamine, a common constituent ofvarious animal and human excretions. In carrying out the tests, 500 mg.of the adsorbent solid were placed in a 43.5 ml. vial and thetriethylamine added in sufficient quantity to give a weight loading oftriethylamine of 4.37%. For purposes of comparison, triethylamine wasplaced in a vial with no adsorbent. The headspace vapors in the vialswere analyzed in the same manner as described hereinabove. The adsorbentidentified as LZ-20 in Example 2, and in subsequent Examples, is asteam-stabilized form of zeolite Y prepared in a manner essentially thesame as employed in the preparation of LZ-10 except the steamingconditions were less rigorous resulting in a product having a wateradsorption capacity of about 10 weight percent at Standard Conditions,and a sodium content (as Na₂ O) of 0.2 weight percent (anhydrous basis).The adsorbent identified as LZ105-5 in Example 9 and subsequent exampleswas a zeolite of the ZSM-5 type prepared in the absence of organictemplating material to produce a zeolite having a SiO₂ /Al₂ O₃ molarratio of about 36.7 and a Na₂ /Al₂ ratio of 1.19. The adsorbentcomposition of Example 5 was equal parts by weight mixture of LZ-10 andsilicalite. The analytical results are set forth below in tabular form.

                  TABLE I                                                         ______________________________________                                                           TEA in Headspace,                                                 Adsorbent   ppm                                                        ______________________________________                                                 None          470.                                                   Ex. 2    LZ-20         .003                                                   Ex. 3    LZ-10         .010                                                   Ex. 4    Activated Charcoal                                                                          .017                                                   Ex. 5    LZ-10; Silicalite                                                                           .033                                                   Ex. 6    Silica gel    19.74                                                  Ex. 7    Silicalite    <108.                                                  Ex. 8    NaHCO.sub.3   <108.                                                  Ex. 9    LZ-105-5      <108.                                                  ______________________________________                                    

EXAMPLE 10

A combination of isovaleric acid and butyl mercaptan (butanethiol) wasused in increasing amounts to determine the effects of various weightpercent loading on a composition of equal parts by weight of LZ-10 andsilicalite on the residual headspace concentration. The results are:

                  TABLE II                                                        ______________________________________                                        Weight Percent Loading                                                                          Remaining (ppm) In Air                                      On Adsorbent      After Treatment                                             Isovaleric            Isovaleric                                              Acid      Butanethiol Acid      Butanethiol                                   ______________________________________                                        No adsorbent          1.58      206                                           0.93      0.83        .0012     .0011                                         1.86      1.67        .0011     .0011                                         2.79      2.65        .0019     .0097                                         3.71      3.33        .0014     .0136                                         7.43      6.67        .0021     .0762                                         9.29      8.34        .0174     4.73                                          ______________________________________                                    

EXAMPLES 11-18

The same type of test as Examples 2-9 was conducted on a number of othermaterials. The results are:

                  TABLE III                                                       ______________________________________                                                         Headspace Composition;                                                        ppm                                                                             Isovaleric                                                        Adsorbent   Acid      Butanethiol                                      ______________________________________                                                 None          1.58      206                                          Ex 11    LZ-20         .0104     .2266                                        Ex 12    LZ-10         .0038     .5768                                        Ex 13    LZ-105-5      .5846     .0659                                        Ex 14    Silicalite    .3160     4.326                                        Ex 15    Silica Gel    .8216     6.386                                        Ex 16    Silicalite; LZ-10*                                                                          .0237     .2060                                        Ex 17    LZ-105-5; LZ-20*                                                                            .0111     .0659                                        Ex 18    Silicalite; LZ-20*                                                                          .0174     .0082                                        ______________________________________                                         *Equal parts by weight                                                   

EXAMPLE 19

The samples from Examples 11-18 were allowed to remain capped at roomtemperature and re-tested after twenty-four hours. The following resultswere obtained:

                  TABLE IV                                                        ______________________________________                                                     Headspace Composition;                                                        ppm                                                                             Isovaleric                                                     Adsorbent      Acid      Butanethiol                                          ______________________________________                                        None           1.58      206                                                  Silicalite     .0458     .1133                                                LZ-20          .0190     .7416                                                LZ-10          .0790     2.06                                                 LZ-105-5       .4266     2.47                                                 Silicalite; LZ-10                                                                            .5214     28.84                                                ______________________________________                                    

EXAMPLE 20

To establish that certain highly siliceous molecular sieves lacking therequisite degree of hydrophobicity do not qualify as adsorbents for usein this invention, a zeolite Beta having a framework SiO₂ /Al₂ O₃ molarratio of 25.4 and a water sorption capacity of 14.28 weight percent atStandard Conditions, was contacted with isovaleric acid. It was found bya subjective "sniff" test that an appreciable amount of odor due to theisovaleric acid remained after contact with the adsorbent.

EXAMPLE 21

A commercially obtained sanitary napkin (STAYFREE brand available fromthe Johnson & Johnson Company) was worn by a woman during menstruation.The napkin was removed and a marked odor was detected even though thesanitary napkin was perfumed. A mixture of equal parts by weight ofactivated silicalite and zeolite LZ-10 were sprinkled on the stainedportion sufficient to cover that area and no odor was detected.

EXAMPLE 22

Two non woven sheets comprised of cellulose were assembled into alaminate sandwich containing a relatively uniform distribution ofsiliceous molecular sieves. Each sheet was about 1 millimeter inthickness and about 12 centimeters wide and 25 centimeters in length.The sheets were sealed together using polyester to form a single sheetabout 2 millimeters in thickness. The sheet contained about 1 gram of amixture of equal parts by weight of activated silicalite and zeoliteLZ-10.

The sheet was folded double and placed under the top layer of acommercial sanitary napkin (STAYFREE brand available from the Johnson &Johnson Company) and worn by a woman during menstruation. After use, thenapkin had no detectable odor.

It is claimed:
 1. A fibrous absorbent article for absorbing body fluidscomprising a fibrous material defining a structure suitable forabsorbing body fluids and an effective amount to reduce odors from thebody fluids of crystalline siliceous molecular sieve in which at leastabout 90 percent of the framework tetrahedral oxide units are SiO₂tetrahedra, having pore diameters of at least about 5.5 Angstroms andhaving a capacity for adsorbed water not greater than 10 weight percentwhen measured using a water vapor pressure of 4.6 torr at a temperatureof 25° C. and for a time of two hours.
 2. The fibrous absorbent articleof claim 1 wherein the crystalline siliceous molecular sieve has atleast been partially activated.
 3. The fibrous absorbent article ofclaim 1 wherein the siliceous molecular sieve has a capacity foradsorbed water of not greater than 6 weight percent under StandardConditions.
 4. The fibrous absorbent article of claim 1 wherein thesiliceous molecular sieve is an aluminosilicate having a framework SiO₂/Al₂ O₂ molar ratio greater than
 35. 5. The fibrous absorbent article ofclaim 4 wherein the aluminosilicate has a SiO₂ /Al₂ O₃ molar ratio offrom 200 to
 500. 6. The fibrous absorbent article of claim 1 wherein thesiliceous molecular sieve comprises a silica polymorph.
 7. The fibrousabsorbent article of claim 1 wherein the siliceous molecular sievecomprises a mixture of a silica polymorph and an aluminosilicate havinga framework SiO₂ /Al₂ O₃ ratio of from 200 to
 500. 8. The fibrousabsorbent article of claim 1 wherein the siliceous molecular sievecomprises a mixture of a silica polymorph and a type Y zeolite having aframework SiO₂ /Al₂ O₃ ratio of at least 35, said silica polymorph andsaid type Y zeolite each having a capacity for adsorbed water of notgreater than 10 weight percent when measured at Standard Conditions. 9.The fibrous absorbent article of claim 8 wherein the silica polymorphcomprises silicalite and the type Y zeolite is LZ-10.
 10. The fibrousabsorbent article of claim 1 wherein the crystalline siliceous molecularsieve contains less than 0.2 weight percent alkali metal on an anhydrousbasis.
 11. The fibrous absorbent article of claim 1 which comprisesabout 0.01 to 50 grams of said siliceous molecular sieve per 100 cubiccentimeters of article volume.
 12. The fibrous absorbent article ofclaim 1 which comprises about 0.01 to 25 grams of said siliceousmolecular sieve per 100 cubic centimeters of effective area.
 13. Thefibrous absorbent article of claim 1 wherein the fibrous materialstructure is a non-woven batt.
 14. The fibrous absorbent article ofclaim 1 wherein the siliceous molecular sieve is dispersed in thefibrous material.
 15. The fibrous absorbent article of claim 1 whereinthe siliceous molecular sieve is contained in a fluid permeablestructure through which the siliceous molecular sieve cannot pass. 16.The fibrous absorbent article of claim 5 which is a catamenial article.17. The fibrous absorbent article of claim 16 which is a sanitarynapkin.
 18. The fibrous absorbent article of claim 17 which containsabout 0.01 to 10 grams of siliceous molecular sieve.
 19. The fibrousabsorbent article of claim 17 in which two siliceous molecular sievesare contained within a sandwich structure of two fluid permeable sheetswhich sheets are positioned within the sanitary napkin.
 20. The fibrousabsorbent article of claim 19 which contains superabsorber.